Predicting the potential distribution of the cattle fever tick Rhipicephalus annulatus (Acari: Ixodidae) using ecological niche modeling

Rhipicephalus annulatus is a tick species of veterinary importance due to its potential to transmit babesiosis to cattle. This species has a Holarctic distribution with some Afrotropical records and is one-host species of veterinary importance. This study was carried out from September 2021 to February 2022 at 6 Egyptian collection sites, and a total of 1150 cattle were scanned randomly to collect ticks. A total of 1095 tick specimens were collected and identified as R. annulatus using taxonomic keys. Males were found on all parts of the cattle except the head and around the eyes, but females were found on all parts; in addition, the highest number of specimens was gathered from the udder, (neck and chest), and belly. Maximum entropy (MaxEnt) modeling was used to predict the potential global distribution of R. annulatus. The MaxEnt model performed better than random with an average test area under the curve (AUC) value of 0.96, and model predictions were significantly better than random and gave (AUC) ratios above the null expectations in the partial receiver operating characteristic (pROC) analyses (P < 0.001). Based on correlation analyses, a set of 9 variables was selected for species from 15 bioclimatic and 5 normalized difference vegetation index (NDVI) variables. The study showed that the current distribution of R. annulatus is estimated to occur across Asia, Africa, Europe, South America, and North America. Annual mean temperature (Bio1) and median NDVI had the highest effect on the distribution of this species. The environmentally suitable habitat for R. annulatus sharply increased with increasing annual mean temperature (Bio1). These results can be used for making effective control planning decisions in areas suitable to this vector of many diseases worldwide.